~bzr-pqm/bzr/bzr.dev

#!/usr/bin/env python

"""\

Read in a changeset output, and process it into a Changeset object.

"""

import bzrlib, bzrlib.changeset

import common

class BadChangeset(Exception): pass

class MalformedHeader(BadChangeset): pass

class MalformedPatches(BadChangeset): pass

class MalformedFooter(BadChangeset): pass

def _unescape(name):

    """Now we want to find the filename effected.

    Unfortunately the filename is written out as

    repr(filename), which means that it surrounds

    the name with quotes which may be single or double

    (single is preferred unless there is a single quote in

    the filename). And some characters will be escaped.

    TODO:   There has to be some pythonic way of undo-ing the

            representation of a string rather than using eval.

    """

    delimiter = name[0]

    if name[-1] != delimiter:

        raise BadChangeset('Could not properly parse the'

                ' filename: %r' % name)

    # We need to handle escaped hexadecimals too.

    return name[1:-1].replace('\"', '"').replace("\'", "'")

class ChangesetInfo(object):

    """This is the intermediate class that gets filled out as

    the file is read.

    """

    def __init__(self):

        self.committer = None

        self.date = None

        self.message = None

        self.revno = None

        self.revision = None

        self.revision_sha1 = None

        self.precursor = None

        self.precursor_sha1 = None

        self.precursor_revno = None

        self.timestamp = None

        self.timezone = None

        self.tree_root_id = None

        self.file_ids = None

        self.old_file_ids = None

        self.actions = [] #this is the list of things that happened

        self.id2path = {} # A mapping from file id to path name

        self.path2id = {} # The reverse mapping

        self.id2parent = {} # A mapping from a given id to it's parent id

        self.old_id2path = {}

        self.old_path2id = {}

        self.old_id2parent = {}

    def __str__(self):

        import pprint

        return pprint.pformat(self.__dict__)

    def create_maps(self):

        """Go through the individual id sections, and generate the 

        id2path and path2id maps.

        """

        # Rather than use an empty path, the changeset code seems 

        # to like to use "./." for the tree root.

        self.id2path[self.tree_root_id] = './.'

        self.path2id['./.'] = self.tree_root_id

        self.id2parent[self.tree_root_id] = bzrlib.changeset.NULL_ID

        self.old_id2path = self.id2path.copy()

        self.old_path2id = self.path2id.copy()

        self.old_id2parent = self.id2parent.copy()

        if self.file_ids:

            for info in self.file_ids:

                path, f_id, parent_id = info.split('\t')

                self.id2path[f_id] = path

                self.path2id[path] = f_id

                self.id2parent[f_id] = parent_id

        if self.old_file_ids:

            for info in self.old_file_ids:

                path, f_id, parent_id = info.split('\t')

                self.old_id2path[f_id] = path

                self.old_path2id[path] = f_id

                self.old_id2parent[f_id] = parent_id

    def get_changeset(self):

        """Create a changeset from the data contained within."""

        from bzrlib.changeset import Changeset, ChangesetEntry, \

            PatchApply, ReplaceContents

        cset = Changeset()

        entry = ChangesetEntry(self.tree_root_id, 

                bzrlib.changeset.NULL_ID, './.')

        cset.add_entry(entry)

        for info, lines in self.actions:

            parts = info.split(' ')

            action = parts[0]

            kind = parts[1]

            extra = ' '.join(parts[2:])

            if action == 'renamed':

                old_path, new_path = extra.split(' => ')

                old_path = _unescape(old_path)

                new_path = _unescape(new_path)

                new_id = self.path2id[new_path]

                old_id = self.old_path2id[old_path]

                assert old_id == new_id

                new_parent = self.id2parent[new_id]

                old_parent = self.old_id2parent[old_id]

                entry = ChangesetEntry(old_id, old_parent, old_path)

                entry.new_path = new_path

                entry.new_parent = new_parent

                if lines:

                    entry.contents_change = PatchApply(''.join(lines))

            elif action == 'removed':

                old_path = _unescape(extra)

                old_id = self.old_path2id[old_path]

                old_parent = self.old_id2parent[old_id]

                entry = ChangesetEntry(old_id, old_parent, old_path)

                entry.new_path = None

                entry.new_parent = None

                if lines:

                    # Technically a removed should be a ReplaceContents()

                    # Where you need to have the old contents

                    # But at most we have a remove style patch.

                    #entry.contents_change = ReplaceContents()

                    pass

            elif action == 'added':

                new_path = _unescape(extra)

                new_id = self.path2id[new_path]

                new_parent = self.id2parent[new_id]

                entry = ChangesetEntry(new_id, new_parent, new_path)

                entry.path = None

                entry.parent = None

                if lines:

                    # Technically an added should be a ReplaceContents()

                    # Where you need to have the old contents

                    # But at most we have an add style patch.

                    #entry.contents_change = ReplaceContents()

                    entry.contents_change = PatchApply(''.join(lines))

            elif action == 'modified':

                new_path = _unescape(extra)

                new_id = self.path2id[new_path]

                new_parent = self.id2parent[new_id]

                entry = ChangesetEntry(new_id, new_parent, new_path)

                entry.path = None

                entry.parent = None

                if lines:

                    # Technically an added should be a ReplaceContents()

                    # Where you need to have the old contents

                    # But at most we have an add style patch.

                    #entry.contents_change = ReplaceContents()

                    entry.contents_change = PatchApply(''.join(lines))

            else:

                raise BadChangeset('Unrecognized action: %r' % action)

            cset.add_entry(entry)

        return cset

class ChangesetReader(object):

    """This class reads in a changeset from a file, and returns

    a Changeset object, which can then be applied against a tree.

    """

    def __init__(self, from_file):

        """Read in the changeset from the file.

        :param from_file: A file-like object (must have iterator support).

        """

        object.__init__(self)

        self.from_file = from_file

        self.info = ChangesetInfo()

        # We put the actual inventory ids in the footer, so that the patch

        # is easier to read for humans.

        # Unfortunately, that means we need to read everything before we

        # can create a proper changeset.

        self._read_header()

        next_line = self._read_patches()

        if next_line is not None:

            self._read_footer(next_line)

    def get_info(self):

        """Create the actual changeset object.

        """

        self.info.create_maps()

        return self.info

    def _read_header(self):

        """Read the bzr header"""

        header = common.get_header()

        for head_line, line in zip(header, self.from_file):

            if (line[:2] != '# '

                    or line[-1] != '\n'

                    or line[2:-1] != head_line):

                raise MalformedHeader('Did not read the opening'

                    ' header information.')

        for line in self.from_file:

            if self._handle_info_line(line) is not None:

                break

    def _handle_info_line(self, line, in_footer=False):

        """Handle reading a single line.

        This may call itself, in the case that we read_multi,

        and then had a dangling line on the end.

        """

        # The bzr header is terminated with a blank line

        # which does not start with #

        next_line = None

        if line[:1] == '\n':

            return 'break'

        if line[:2] != '# ':

            raise MalformedHeader('Opening bzr header did not start with #')

        line = line[2:-1] # Remove the '# '

        if not line:

            return # Ignore blank lines

        if in_footer and line in ('BEGIN BZR FOOTER', 'END BZR FOOTER'):

            return

        loc = line.find(': ')

        if loc != -1:

            key = line[:loc]

            value = line[loc+2:]

            if not value:

                value, next_line = self._read_many()

        else:

            if line[-1:] == ':':

                key = line[:-1]

                value, next_line = self._read_many()

            else:

                raise MalformedHeader('While looking for key: value pairs,'

                        ' did not find the colon %r' % (line))

        key = key.replace(' ', '_')

        if hasattr(self.info, key):

            if getattr(self.info, key) is None:

                setattr(self.info, key, value)

            else:

                raise MalformedHeader('Duplicated Key: %s' % key)

        else:

            # What do we do with a key we don't recognize

            raise MalformedHeader('Unknown Key: %s' % key)

        if next_line:

            self._handle_info_line(next_line, in_footer=in_footer)

    def _read_many(self):

        """If a line ends with no entry, that means that it should be

        followed with multiple lines of values.

        This detects the end of the list, because it will be a line that

        does not start with '#    '. Because it has to read that extra

        line, it returns the tuple: (values, next_line)

        """

        values = []

        for line in self.from_file:

            if line[:5] != '#    ':

                return values, line

            values.append(line[5:-1])

        return values, None

    def _read_one_patch(self, first_line=None):

        """Read in one patch, return the complete patch, along with

        the next line.

        :return: action, lines, next_line, do_continue

        """

        first = True

        action = None

        def parse_firstline(line):

            if line[:1] == '#':

                return None

            if line[:3] != '***':

                raise MalformedPatches('The first line of all patches'

                    ' should be a bzr meta line "***"')

            return line[4:-1]

        if first_line is not None:

            action = parse_firstline(first_line)

            first = False

            if action is None:

                return None, [], first_line, False

        lines = []

        for line in self.from_file:

            if first:

                action = parse_firstline(line)

                first = False

                if action is None:

                    return None, [], line, False

            else:

                if line[:3] == '***':

                    return action, lines, line, True

                elif line[:1] == '#':

                    return action, lines, line, False

                lines.append(line)

        return action, lines, None, False

    def _read_patches(self):

        next_line = None

        do_continue = True

        while do_continue:

            action, lines, next_line, do_continue = \

                    self._read_one_patch(next_line)

            if action is not None:

                self.info.actions.append((action, lines))

        return next_line

    def _read_footer(self, first_line=None):

        """Read the rest of the meta information.

        :param first_line:  The previous step iterates past what it

                            can handle. That extra line is given here.

        """

        if first_line is not None:

            if self._handle_info_line(first_line, in_footer=True) is not None:

                return

        for line in self.from_file:

            if self._handle_info_line(line, in_footer=True) is not None:

                break

def read_changeset(from_file):

    """Read in a changeset from a filelike object (must have "readline" support), and

    parse it into a Changeset object.

    """

    cr = ChangesetReader(from_file)

    info = cr.get_info()

    return info